Casino Aztar goes bust on its attempt to keep some of its Evansville employees from unionizing. Dealers and floor supervisors at the casino had asked for permission to hold a union election. However, Columbia Sussex, which owns the riverboat, claimed some of the employees asking for permission to join the United Auto Workers Union were ineligible to join a union because they were supervisors. But the National Labor Relations Board disagrees. That means a union vote at the Boat could come in a matter of months.